// SPDX-License-Identifier: GPL-2.0-only
/*
 *	linux/kernel/resource.c
 *
 * Copyright (C) 1999	Linus Torvalds
 * Copyright (C) 1999	Martin Mares <mj@ucw.cz>
 *
 * Arbitrary resource management.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <generated/deconfig.h>
#include <linux/export.h>
#include <linux/errno.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/fs.h>
#include <linux/proc_fs.h>
#include <linux/sched.h>
#include <linux/seq_file.h>
#include <linux/device.h>
#include <linux/pfn.h>
#include <linux/mm.h>
#include <linux/resource_ext.h>
#include <asm/io.h>


struct resource ioport_resource = {
	.name	= "PCI IO",
	.start	= 0,
	.end	= IO_SPACE_LIMIT,
	.flags	= IORESOURCE_IO,
};
EXPORT_SYMBOL(ioport_resource);

struct resource iomem_resource = {
	.name	= "PCI mem",
	.start	= 0,
	.end	= -1,
	.flags	= IORESOURCE_MEM,
};
EXPORT_SYMBOL(iomem_resource);

///* constraints to be met while allocating resources */
//struct resource_constraint {
//	resource_size_t min, max, align;
//	resource_size_t (*alignf)(void *, const struct resource *,
//			resource_size_t, resource_size_t);
//	void *alignf_data;
//};

static DEFINE_RWLOCK(resource_lock);

///*
// * For memory hotplug, there is no way to free resource entries allocated
// * by boot mem after the system is up. So for reusing the resource entry
// * we need to remember the resource.
// */
//static struct resource *bootmem_resource_free;
//static DEFINE_SPINLOCK(bootmem_resource_lock);

//static struct resource *next_resource(struct resource *p, bool sibling_only)
//{
//	/* Caller wants to traverse through siblings only */
//	if (sibling_only)
//		return p->sibling;

//	if (p->child)
//		return p->child;
//	while (!p->sibling && p->parent)
//		p = p->parent;
//	return p->sibling;
//}

//static void *r_next(struct seq_file *m, void *v, loff_t *pos)
//{
//	struct resource *p = v;
//	(*pos)++;
//	return (void *)next_resource(p, false);
//}

//#ifdef CONFIG_PROC_FS

//enum { MAX_IORES_LEVEL = 5 };

//static void *r_start(struct seq_file *m, loff_t *pos)
//	__acquires(resource_lock)
//{
//	struct resource *p = PDE_DATA(file_inode(m->file));
//	loff_t l = 0;
//	read_lock(&resource_lock);
//	for (p = p->child; p && l < *pos; p = r_next(m, p, &l))
//		;
//	return p;
//}

//static void r_stop(struct seq_file *m, void *v)
//	__releases(resource_lock)
//{
//	read_unlock(&resource_lock);
//}

//static int r_show(struct seq_file *m, void *v)
//{
//	struct resource *root = PDE_DATA(file_inode(m->file));
//	struct resource *r = v, *p;
//	unsigned long long start, end;
//	int width = root->end < 0x10000 ? 4 : 8;
//	int depth;

//	for (depth = 0, p = r; depth < MAX_IORES_LEVEL; depth++, p = p->parent)
//		if (p->parent == root)
//			break;

//	if (file_ns_capable(m->file, &init_user_ns, CAP_SYS_ADMIN)) {
//		start = r->start;
//		end = r->end;
//	} else {
//		start = end = 0;
//	}

//	seq_printf(m, "%*s%0*llx-%0*llx : %s\n",
//			depth * 2, "",
//			width, start,
//			width, end,
//			r->name ? r->name : "<BAD>");
//	return 0;
//}

//static const struct seq_operations resource_op = {
//	.start	= r_start,
//	.next	= r_next,
//	.stop	= r_stop,
//	.show	= r_show,
//};

//static int __init ioresources_init(void)
//{
//	proc_create_seq_data("ioports", 0, NULL, &resource_op,
//			&ioport_resource);
//	proc_create_seq_data("iomem", 0, NULL, &resource_op, &iomem_resource);
//	return 0;
//}
//__initcall(ioresources_init);

//#endif /* CONFIG_PROC_FS */

//static void free_resource(struct resource *res)
//{
//	if (!res)
//		return;

//	if (!PageSlab(virt_to_head_page(res))) {
//		spin_lock(&bootmem_resource_lock);
//		res->sibling = bootmem_resource_free;
//		bootmem_resource_free = res;
//		spin_unlock(&bootmem_resource_lock);
//	} else {
//		kfree(res);
//	}
//}

//static struct resource *alloc_resource(gfp_t flags)
//{
//	struct resource *res = NULL;

//	spin_lock(&bootmem_resource_lock);
//	if (bootmem_resource_free) {
//		res = bootmem_resource_free;
//		bootmem_resource_free = res->sibling;
//	}
//	spin_unlock(&bootmem_resource_lock);

//	if (res)
//		memset(res, 0, sizeof(struct resource));
//	else
//		res = kzalloc(sizeof(struct resource), flags);

//	return res;
//}

/* Return the conflict entry if you can't request it */
static struct resource * __request_resource(struct resource *root, struct resource *new)
{
	resource_size_t start = new->start;
	resource_size_t end = new->end;
	struct resource *tmp, **p;

	if (end < start)
		return root;
	if (start < root->start)
		return root;
	if (end > root->end)
		return root;
	p = &root->child;
	for (;;) {
		tmp = *p;
		if (!tmp || tmp->start > end) {
			new->sibling = tmp;
			*p = new;
			new->parent = root;
			return NULL;
		}
		p = &tmp->sibling;
		if (tmp->end < start)
			continue;
		return tmp;
	}
}

static int __release_resource(struct resource *old, bool release_child)
{
	struct resource *tmp, **p, *chd;

	p = &old->parent->child;
	for (;;) {
		tmp = *p;
		if (!tmp)
			break;
		if (tmp == old) {
			if (release_child || !(tmp->child)) {
				*p = tmp->sibling;
			} else {
				for (chd = tmp->child;; chd = chd->sibling) {
					chd->parent = tmp->parent;
					if (!(chd->sibling))
						break;
				}
				*p = tmp->child;
				chd->sibling = tmp->sibling;
			}
			old->parent = NULL;
			return 0;
		}
		p = &tmp->sibling;
	}
	return -EINVAL;
}

static void __release_child_resources(struct resource *r)
{
	struct resource *tmp, *p;
	resource_size_t size;

	p = r->child;
	r->child = NULL;
	while (p) {
		tmp = p;
		p = p->sibling;

		tmp->parent = NULL;
		tmp->sibling = NULL;
		__release_child_resources(tmp);

		printk(KERN_DEBUG "release child resource %pR\n", tmp);
		/* need to restore size, and keep flags */
		size = resource_size(tmp);
		tmp->start = 0;
		tmp->end = size - 1;
	}
}

void release_child_resources(struct resource *r)
{
	write_lock(&resource_lock);
	__release_child_resources(r);
	write_unlock(&resource_lock);
}

/**
 * request_resource_conflict - request and reserve an I/O or memory resource
 * @root: root resource descriptor
 * @new: resource descriptor desired by caller
 *
 * Returns 0 for success, conflict resource on error.
 */
struct resource *request_resource_conflict(struct resource *root, struct resource *new)
{
	struct resource *conflict;

	write_lock(&resource_lock);
	conflict = __request_resource(root, new);
	write_unlock(&resource_lock);
	return conflict;
}

/**
 * request_resource - request and reserve an I/O or memory resource
 * @root: root resource descriptor
 * @new: resource descriptor desired by caller
 *
 * Returns 0 for success, negative error code on error.
 */
int request_resource(struct resource *root, struct resource *new)
{
	struct resource *conflict;

	conflict = request_resource_conflict(root, new);
	return conflict ? -EBUSY : 0;
}

EXPORT_SYMBOL(request_resource);

/**
 * release_resource - release a previously reserved resource
 * @old: resource pointer
 */
int release_resource(struct resource *old)
{
	int retval;

	write_lock(&resource_lock);
	retval = __release_resource(old, true);
	write_unlock(&resource_lock);
	return retval;
}

EXPORT_SYMBOL(release_resource);

///**
// * Finds the lowest iomem resource that covers part of [@start..@end].  The
// * caller must specify @start, @end, @flags, and @desc (which may be
// * IORES_DESC_NONE).
// *
// * If a resource is found, returns 0 and @*res is overwritten with the part
// * of the resource that's within [@start..@end]; if none is found, returns
// * -ENODEV.  Returns -EINVAL for invalid parameters.
// *
// * This function walks the whole tree and not just first level children
// * unless @first_lvl is true.
// *
// * @start:	start address of the resource searched for
// * @end:	end address of same resource
// * @flags:	flags which the resource must have
// * @desc:	descriptor the resource must have
// * @first_lvl:	walk only the first level children, if set
// * @res:	return ptr, if resource found
// */
//static int find_next_iomem_res(resource_size_t start, resource_size_t end,
//			       unsigned long flags, unsigned long desc,
//			       bool first_lvl, struct resource *res)
//{
//	bool siblings_only = true;
//	struct resource *p;

//	if (!res)
//		return -EINVAL;

//	if (start >= end)
//		return -EINVAL;

//	read_lock(&resource_lock);

//	for (p = iomem_resource.child; p; p = next_resource(p, siblings_only)) {
//		/* If we passed the resource we are looking for, stop */
//		if (p->start > end) {
//			p = NULL;
//			break;
//		}

//		/* Skip until we find a range that matches what we look for */
//		if (p->end < start)
//			continue;

//		/*
//		 * Now that we found a range that matches what we look for,
//		 * check the flags and the descriptor. If we were not asked to
//		 * use only the first level, start looking at children as well.
//		 */
//		siblings_only = first_lvl;

//		if ((p->flags & flags) != flags)
//			continue;
//		if ((desc != IORES_DESC_NONE) && (desc != p->desc))
//			continue;

//		/* Found a match, break */
//		break;
//	}

//	if (p) {
//		/* copy data */
//		*res = (struct resource) {
//			.start = max(start, p->start),
//			.end = min(end, p->end),
//			.flags = p->flags,
//			.desc = p->desc,
//			.parent = p->parent,
//		};
//	}

//	read_unlock(&resource_lock);
//	return p ? 0 : -ENODEV;
//}

//static int __walk_iomem_res_desc(resource_size_t start, resource_size_t end,
//				 unsigned long flags, unsigned long desc,
//				 bool first_lvl, void *arg,
//				 int (*func)(struct resource *, void *))
//{
//	struct resource res;
//	int ret = -EINVAL;

//	while (start < end &&
//	       !find_next_iomem_res(start, end, flags, desc, first_lvl, &res)) {
//		ret = (*func)(&res, arg);
//		if (ret)
//			break;

//		start = res.end + 1;
//	}

//	return ret;
//}

///**
// * Walks through iomem resources and calls func() with matching resource
// * ranges. This walks through whole tree and not just first level children.
// * All the memory ranges which overlap start,end and also match flags and
// * desc are valid candidates.
// *
// * @desc: I/O resource descriptor. Use IORES_DESC_NONE to skip @desc check.
// * @flags: I/O resource flags
// * @start: start addr
// * @end: end addr
// * @arg: function argument for the callback @func
// * @func: callback function that is called for each qualifying resource area
// *
// * NOTE: For a new descriptor search, define a new IORES_DESC in
// * <linux/ioport.h> and set it in 'desc' of a target resource entry.
// */
//int walk_iomem_res_desc(unsigned long desc, unsigned long flags, u64 start,
//		u64 end, void *arg, int (*func)(struct resource *, void *))
//{
//	return __walk_iomem_res_desc(start, end, flags, desc, false, arg, func);
//}
//EXPORT_SYMBOL_GPL(walk_iomem_res_desc);

///*
// * This function calls the @func callback against all memory ranges of type
// * System RAM which are marked as IORESOURCE_SYSTEM_RAM and IORESOUCE_BUSY.
// * Now, this function is only for System RAM, it deals with full ranges and
// * not PFNs. If resources are not PFN-aligned, dealing with PFNs can truncate
// * ranges.
// */
//int walk_system_ram_res(u64 start, u64 end, void *arg,
//			int (*func)(struct resource *, void *))
//{
//	unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;

//	return __walk_iomem_res_desc(start, end, flags, IORES_DESC_NONE, false,
//				     arg, func);
//}

///*
// * This function calls the @func callback against all memory ranges, which
// * are ranges marked as IORESOURCE_MEM and IORESOUCE_BUSY.
// */
//int walk_mem_res(u64 start, u64 end, void *arg,
//		 int (*func)(struct resource *, void *))
//{
//	unsigned long flags = IORESOURCE_MEM | IORESOURCE_BUSY;

//	return __walk_iomem_res_desc(start, end, flags, IORES_DESC_NONE, false,
//				     arg, func);
//}

///*
// * This function calls the @func callback against all memory ranges of type
// * System RAM which are marked as IORESOURCE_SYSTEM_RAM and IORESOUCE_BUSY.
// * It is to be used only for System RAM.
// *
// * This will find System RAM ranges that are children of top-level resources
// * in addition to top-level System RAM resources.
// */
//int walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
//			  void *arg, int (*func)(unsigned long, unsigned long, void *))
//{
//	resource_size_t start, end;
//	unsigned long flags;
//	struct resource res;
//	unsigned long pfn, end_pfn;
//	int ret = -EINVAL;

//	start = (u64) start_pfn << PAGE_SHIFT;
//	end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1;
//	flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
//	while (start < end &&
//	       !find_next_iomem_res(start, end, flags, IORES_DESC_NONE,
//				    false, &res)) {
//		pfn = PFN_UP(res.start);
//		end_pfn = PFN_DOWN(res.end + 1);
//		if (end_pfn > pfn)
//			ret = (*func)(pfn, end_pfn - pfn, arg);
//		if (ret)
//			break;
//		start = res.end + 1;
//	}
//	return ret;
//}

//static int __is_ram(unsigned long pfn, unsigned long nr_pages, void *arg)
//{
//	return 1;
//}

///*
// * This generic page_is_ram() returns true if specified address is
// * registered as System RAM in iomem_resource list.
// */
//int __weak page_is_ram(unsigned long pfn)
//{
//	return walk_system_ram_range(pfn, 1, NULL, __is_ram) == 1;
//}
//EXPORT_SYMBOL_GPL(page_is_ram);

///**
// * region_intersects() - determine intersection of region with known resources
// * @start: region start address
// * @size: size of region
// * @flags: flags of resource (in iomem_resource)
// * @desc: descriptor of resource (in iomem_resource) or IORES_DESC_NONE
// *
// * Check if the specified region partially overlaps or fully eclipses a
// * resource identified by @flags and @desc (optional with IORES_DESC_NONE).
// * Return REGION_DISJOINT if the region does not overlap @flags/@desc,
// * return REGION_MIXED if the region overlaps @flags/@desc and another
// * resource, and return REGION_INTERSECTS if the region overlaps @flags/@desc
// * and no other defined resource. Note that REGION_INTERSECTS is also
// * returned in the case when the specified region overlaps RAM and undefined
// * memory holes.
// *
// * region_intersect() is used by memory remapping functions to ensure
// * the user is not remapping RAM and is a vast speed up over walking
// * through the resource table page by page.
// */
//int region_intersects(resource_size_t start, size_t size, unsigned long flags,
//		      unsigned long desc)
//{
//	struct resource res;
//	int type = 0; int other = 0;
//	struct resource *p;

//	res.start = start;
//	res.end = start + size - 1;

//	read_lock(&resource_lock);
//	for (p = iomem_resource.child; p ; p = p->sibling) {
//		bool is_type = (((p->flags & flags) == flags) &&
//				((desc == IORES_DESC_NONE) ||
//				 (desc == p->desc)));

//		if (resource_overlaps(p, &res))
//			is_type ? type++ : other++;
//	}
//	read_unlock(&resource_lock);

//	if (other == 0)
//		return type ? REGION_INTERSECTS : REGION_DISJOINT;

//	if (type)
//		return REGION_MIXED;

//	return REGION_DISJOINT;
//}
//EXPORT_SYMBOL_GPL(region_intersects);

//void __weak arch_remove_reservations(struct resource *avail)
//{
//}

//static resource_size_t simple_align_resource(void *data,
//					     const struct resource *avail,
//					     resource_size_t size,
//					     resource_size_t align)
//{
//	return avail->start;
//}

//static void resource_clip(struct resource *res, resource_size_t min,
//			  resource_size_t max)
//{
//	if (res->start < min)
//		res->start = min;
//	if (res->end > max)
//		res->end = max;
//}

///*
// * Find empty slot in the resource tree with the given range and
// * alignment constraints
// */
//static int __find_resource(struct resource *root, struct resource *old,
//			 struct resource *new,
//			 resource_size_t  size,
//			 struct resource_constraint *constraint)
//{
//	struct resource *this = root->child;
//	struct resource tmp = *new, avail, alloc;

//	tmp.start = root->start;
//	/*
//	 * Skip past an allocated resource that starts at 0, since the assignment
//	 * of this->start - 1 to tmp->end below would cause an underflow.
//	 */
//	if (this && this->start == root->start) {
//		tmp.start = (this == old) ? old->start : this->end + 1;
//		this = this->sibling;
//	}
//	for(;;) {
//		if (this)
//			tmp.end = (this == old) ?  this->end : this->start - 1;
//		else
//			tmp.end = root->end;

//		if (tmp.end < tmp.start)
//			goto next;

//		resource_clip(&tmp, constraint->min, constraint->max);
//		arch_remove_reservations(&tmp);

//		/* Check for overflow after ALIGN() */
//		avail.start = ALIGN(tmp.start, constraint->align);
//		avail.end = tmp.end;
//		avail.flags = new->flags & ~IORESOURCE_UNSET;
//		if (avail.start >= tmp.start) {
//			alloc.flags = avail.flags;
//			alloc.start = constraint->alignf(constraint->alignf_data, &avail,
//					size, constraint->align);
//			alloc.end = alloc.start + size - 1;
//			if (alloc.start <= alloc.end &&
//			    resource_contains(&avail, &alloc)) {
//				new->start = alloc.start;
//				new->end = alloc.end;
//				return 0;
//			}
//		}

//next:		if (!this || this->end == root->end)
//			break;

//		if (this != old)
//			tmp.start = this->end + 1;
//		this = this->sibling;
//	}
//	return -EBUSY;
//}

///*
// * Find empty slot in the resource tree given range and alignment.
// */
//static int find_resource(struct resource *root, struct resource *new,
//			resource_size_t size,
//			struct resource_constraint  *constraint)
//{
//	return  __find_resource(root, NULL, new, size, constraint);
//}

///**
// * reallocate_resource - allocate a slot in the resource tree given range & alignment.
// *	The resource will be relocated if the new size cannot be reallocated in the
// *	current location.
// *
// * @root: root resource descriptor
// * @old:  resource descriptor desired by caller
// * @newsize: new size of the resource descriptor
// * @constraint: the size and alignment constraints to be met.
// */
//static int reallocate_resource(struct resource *root, struct resource *old,
//			       resource_size_t newsize,
//			       struct resource_constraint *constraint)
//{
//	int err=0;
//	struct resource new = *old;
//	struct resource *conflict;

//	write_lock(&resource_lock);

//	if ((err = __find_resource(root, old, &new, newsize, constraint)))
//		goto out;

//	if (resource_contains(&new, old)) {
//		old->start = new.start;
//		old->end = new.end;
//		goto out;
//	}

//	if (old->child) {
//		err = -EBUSY;
//		goto out;
//	}

//	if (resource_contains(old, &new)) {
//		old->start = new.start;
//		old->end = new.end;
//	} else {
//		__release_resource(old, true);
//		*old = new;
//		conflict = __request_resource(root, old);
//		BUG_ON(conflict);
//	}
//out:
//	write_unlock(&resource_lock);
//	return err;
//}


///**
// * allocate_resource - allocate empty slot in the resource tree given range & alignment.
// * 	The resource will be reallocated with a new size if it was already allocated
// * @root: root resource descriptor
// * @new: resource descriptor desired by caller
// * @size: requested resource region size
// * @min: minimum boundary to allocate
// * @max: maximum boundary to allocate
// * @align: alignment requested, in bytes
// * @alignf: alignment function, optional, called if not NULL
// * @alignf_data: arbitrary data to pass to the @alignf function
// */
//int allocate_resource(struct resource *root, struct resource *new,
//		      resource_size_t size, resource_size_t min,
//		      resource_size_t max, resource_size_t align,
//		      resource_size_t (*alignf)(void *,
//						const struct resource *,
//						resource_size_t,
//						resource_size_t),
//		      void *alignf_data)
//{
//	int err;
//	struct resource_constraint constraint;

//	if (!alignf)
//		alignf = simple_align_resource;

//	constraint.min = min;
//	constraint.max = max;
//	constraint.align = align;
//	constraint.alignf = alignf;
//	constraint.alignf_data = alignf_data;

//	if ( new->parent ) {
//		/* resource is already allocated, try reallocating with
//		   the new constraints */
//		return reallocate_resource(root, new, size, &constraint);
//	}

//	write_lock(&resource_lock);
//	err = find_resource(root, new, size, &constraint);
//	if (err >= 0 && __request_resource(root, new))
//		err = -EBUSY;
//	write_unlock(&resource_lock);
//	return err;
//}

//EXPORT_SYMBOL(allocate_resource);

///**
// * lookup_resource - find an existing resource by a resource start address
// * @root: root resource descriptor
// * @start: resource start address
// *
// * Returns a pointer to the resource if found, NULL otherwise
// */
//struct resource *lookup_resource(struct resource *root, resource_size_t start)
//{
//	struct resource *res;

//	read_lock(&resource_lock);
//	for (res = root->child; res; res = res->sibling) {
//		if (res->start == start)
//			break;
//	}
//	read_unlock(&resource_lock);

//	return res;
//}

/*
 * Insert a resource into the resource tree. If successful, return NULL,
 * otherwise return the conflicting resource (compare to __request_resource())
 */
static struct resource * __insert_resource(struct resource *parent, struct resource *new)
{
	struct resource *first, *next;

	for (;; parent = first) {
		first = __request_resource(parent, new);
		if (!first)
			return first;

		if (first == parent)
			return first;
		if (WARN_ON(first == new))	/* duplicated insertion */
			return first;

		if ((first->start > new->start) || (first->end < new->end))
			break;
		if ((first->start == new->start) && (first->end == new->end))
			break;
	}

	for (next = first; ; next = next->sibling) {
		/* Partial overlap? Bad, and unfixable */
		if (next->start < new->start || next->end > new->end)
			return next;
		if (!next->sibling)
			break;
		if (next->sibling->start > new->end)
			break;
	}

	new->parent = parent;
	new->sibling = next->sibling;
	new->child = first;

	next->sibling = NULL;
	for (next = first; next; next = next->sibling)
		next->parent = new;

	if (parent->child == first) {
		parent->child = new;
	} else {
		next = parent->child;
		while (next->sibling != first)
			next = next->sibling;
		next->sibling = new;
	}
	return NULL;
}

/**
 * insert_resource_conflict - Inserts resource in the resource tree
 * @parent: parent of the new resource
 * @new: new resource to insert
 *
 * Returns 0 on success, conflict resource if the resource can't be inserted.
 *
 * This function is equivalent to request_resource_conflict when no conflict
 * happens. If a conflict happens, and the conflicting resources
 * entirely fit within the range of the new resource, then the new
 * resource is inserted and the conflicting resources become children of
 * the new resource.
 *
 * This function is intended for producers of resources, such as FW modules
 * and bus drivers.
 */
struct resource *insert_resource_conflict(struct resource *parent, struct resource *new)
{
	struct resource *conflict;

	write_lock(&resource_lock);
	conflict = __insert_resource(parent, new);
	write_unlock(&resource_lock);
	return conflict;
}

/**
 * insert_resource - Inserts a resource in the resource tree
 * @parent: parent of the new resource
 * @new: new resource to insert
 *
 * Returns 0 on success, -EBUSY if the resource can't be inserted.
 *
 * This function is intended for producers of resources, such as FW modules
 * and bus drivers.
 */
int insert_resource(struct resource *parent, struct resource *new)
{
	struct resource *conflict;

	conflict = insert_resource_conflict(parent, new);
	return conflict ? -EBUSY : 0;
}
EXPORT_SYMBOL_GPL(insert_resource);

///**
// * insert_resource_expand_to_fit - Insert a resource into the resource tree
// * @root: root resource descriptor
// * @new: new resource to insert
// *
// * Insert a resource into the resource tree, possibly expanding it in order
// * to make it encompass any conflicting resources.
// */
//void insert_resource_expand_to_fit(struct resource *root, struct resource *new)
//{
//	if (new->parent)
//		return;

//	write_lock(&resource_lock);
//	for (;;) {
//		struct resource *conflict;

//		conflict = __insert_resource(root, new);
//		if (!conflict)
//			break;
//		if (conflict == root)
//			break;

//		/* Ok, expand resource to cover the conflict, then try again .. */
//		if (conflict->start < new->start)
//			new->start = conflict->start;
//		if (conflict->end > new->end)
//			new->end = conflict->end;

//		printk("Expanded resource %s due to conflict with %s\n", new->name, conflict->name);
//	}
//	write_unlock(&resource_lock);
//}

///**
// * remove_resource - Remove a resource in the resource tree
// * @old: resource to remove
// *
// * Returns 0 on success, -EINVAL if the resource is not valid.
// *
// * This function removes a resource previously inserted by insert_resource()
// * or insert_resource_conflict(), and moves the children (if any) up to
// * where they were before.  insert_resource() and insert_resource_conflict()
// * insert a new resource, and move any conflicting resources down to the
// * children of the new resource.
// *
// * insert_resource(), insert_resource_conflict() and remove_resource() are
// * intended for producers of resources, such as FW modules and bus drivers.
// */
//int remove_resource(struct resource *old)
//{
//	int retval;

//	write_lock(&resource_lock);
//	retval = __release_resource(old, false);
//	write_unlock(&resource_lock);
//	return retval;
//}
//EXPORT_SYMBOL_GPL(remove_resource);

//static int __adjust_resource(struct resource *res, resource_size_t start,
//				resource_size_t size)
//{
//	struct resource *tmp, *parent = res->parent;
//	resource_size_t end = start + size - 1;
//	int result = -EBUSY;

//	if (!parent)
//		goto skip;

//	if ((start < parent->start) || (end > parent->end))
//		goto out;

//	if (res->sibling && (res->sibling->start <= end))
//		goto out;

//	tmp = parent->child;
//	if (tmp != res) {
//		while (tmp->sibling != res)
//			tmp = tmp->sibling;
//		if (start <= tmp->end)
//			goto out;
//	}

//skip:
//	for (tmp = res->child; tmp; tmp = tmp->sibling)
//		if ((tmp->start < start) || (tmp->end > end))
//			goto out;

//	res->start = start;
//	res->end = end;
//	result = 0;

// out:
//	return result;
//}

///**
// * adjust_resource - modify a resource's start and size
// * @res: resource to modify
// * @start: new start value
// * @size: new size
// *
// * Given an existing resource, change its start and size to match the
// * arguments.  Returns 0 on success, -EBUSY if it can't fit.
// * Existing children of the resource are assumed to be immutable.
// */
//int adjust_resource(struct resource *res, resource_size_t start,
//		    resource_size_t size)
//{
//	int result;

//	write_lock(&resource_lock);
//	result = __adjust_resource(res, start, size);
//	write_unlock(&resource_lock);
//	return result;
//}
//EXPORT_SYMBOL(adjust_resource);

//static void __init
//__reserve_region_with_split(struct resource *root, resource_size_t start,
//			    resource_size_t end, const char *name)
//{
//	struct resource *parent = root;
//	struct resource *conflict;
//	struct resource *res = alloc_resource(GFP_ATOMIC);
//	struct resource *next_res = NULL;
//	int type = resource_type(root);

//	if (!res)
//		return;

//	res->name = name;
//	res->start = start;
//	res->end = end;
//	res->flags = type | IORESOURCE_BUSY;
//	res->desc = IORES_DESC_NONE;

//	while (1) {

//		conflict = __request_resource(parent, res);
//		if (!conflict) {
//			if (!next_res)
//				break;
//			res = next_res;
//			next_res = NULL;
//			continue;
//		}

//		/* conflict covered whole area */
//		if (conflict->start <= res->start &&
//				conflict->end >= res->end) {
//			free_resource(res);
//			WARN_ON(next_res);
//			break;
//		}

//		/* failed, split and try again */
//		if (conflict->start > res->start) {
//			end = res->end;
//			res->end = conflict->start - 1;
//			if (conflict->end < end) {
//				next_res = alloc_resource(GFP_ATOMIC);
//				if (!next_res) {
//					free_resource(res);
//					break;
//				}
//				next_res->name = name;
//				next_res->start = conflict->end + 1;
//				next_res->end = end;
//				next_res->flags = type | IORESOURCE_BUSY;
//				next_res->desc = IORES_DESC_NONE;
//			}
//		} else {
//			res->start = conflict->end + 1;
//		}
//	}

//}

//void __init
//reserve_region_with_split(struct resource *root, resource_size_t start,
//			  resource_size_t end, const char *name)
//{
//	int abort = 0;

//	write_lock(&resource_lock);
//	if (root->start > start || root->end < end) {
//		pr_err("requested range [0x%llx-0x%llx] not in root %pr\n",
//		       (unsigned long long)start, (unsigned long long)end,
//		       root);
//		if (start > root->end || end < root->start)
//			abort = 1;
//		else {
//			if (end > root->end)
//				end = root->end;
//			if (start < root->start)
//				start = root->start;
//			pr_err("fixing request to [0x%llx-0x%llx]\n",
//			       (unsigned long long)start,
//			       (unsigned long long)end);
//		}
//		dump_stack();
//	}
//	if (!abort)
//		__reserve_region_with_split(root, start, end, name);
//	write_unlock(&resource_lock);
//}

///**
// * resource_alignment - calculate resource's alignment
// * @res: resource pointer
// *
// * Returns alignment on success, 0 (invalid alignment) on failure.
// */
//resource_size_t resource_alignment(struct resource *res)
//{
//	switch (res->flags & (IORESOURCE_SIZEALIGN | IORESOURCE_STARTALIGN)) {
//	case IORESOURCE_SIZEALIGN:
//		return resource_size(res);
//	case IORESOURCE_STARTALIGN:
//		return res->start;
//	default:
//		return 0;
//	}
//}

///*
// * This is compatibility stuff for IO resources.
// *
// * Note how this, unlike the above, knows about
// * the IO flag meanings (busy etc).
// *
// * request_region creates a new busy region.
// *
// * release_region releases a matching busy region.
// */

//static DECLARE_WAIT_QUEUE_HEAD(muxed_resource_wait);

///**
// * __request_region - create a new busy resource region
// * @parent: parent resource descriptor
// * @start: resource start address
// * @n: resource region size
// * @name: reserving caller's ID string
// * @flags: IO resource flags
// */
//struct resource * __request_region(struct resource *parent,
//				   resource_size_t start, resource_size_t n,
//				   const char *name, int flags)
//{
//	DECLARE_WAITQUEUE(wait, current);
//	struct resource *res = alloc_resource(GFP_KERNEL);
//	struct resource *orig_parent = parent;

//	if (!res)
//		return NULL;

//	res->name = name;
//	res->start = start;
//	res->end = start + n - 1;

//	write_lock(&resource_lock);

//	for (;;) {
//		struct resource *conflict;

//		res->flags = resource_type(parent) | resource_ext_type(parent);
//		res->flags |= IORESOURCE_BUSY | flags;
//		res->desc = parent->desc;

//		conflict = __request_resource(parent, res);
//		if (!conflict)
//			break;
//		/*
//		 * mm/hmm.c reserves physical addresses which then
//		 * become unavailable to other users.  Conflicts are
//		 * not expected.  Warn to aid debugging if encountered.
//		 */
//		if (conflict->desc == IORES_DESC_DEVICE_PRIVATE_MEMORY) {
//			pr_warn("Unaddressable device %s %pR conflicts with %pR",
//				conflict->name, conflict, res);
//		}
//		if (conflict != parent) {
//			if (!(conflict->flags & IORESOURCE_BUSY)) {
//				parent = conflict;
//				continue;
//			}
//		}
//		if (conflict->flags & flags & IORESOURCE_MUXED) {
//			add_wait_queue(&muxed_resource_wait, &wait);
//			write_unlock(&resource_lock);
//			set_current_state(TASK_UNINTERRUPTIBLE);
//			schedule();
//			remove_wait_queue(&muxed_resource_wait, &wait);
//			write_lock(&resource_lock);
//			continue;
//		}
//		/* Uhhuh, that didn't work out.. */
//		free_resource(res);
//		res = NULL;
//		break;
//	}
//	write_unlock(&resource_lock);

//	if (res && orig_parent == &iomem_resource)
//		revoke_devmem(res);

//	return res;
//}
//EXPORT_SYMBOL(__request_region);

///**
// * __release_region - release a previously reserved resource region
// * @parent: parent resource descriptor
// * @start: resource start address
// * @n: resource region size
// *
// * The described resource region must match a currently busy region.
// */
//void __release_region(struct resource *parent, resource_size_t start,
//		      resource_size_t n)
//{
//	struct resource **p;
//	resource_size_t end;

//	p = &parent->child;
//	end = start + n - 1;

//	write_lock(&resource_lock);

//	for (;;) {
//		struct resource *res = *p;

//		if (!res)
//			break;
//		if (res->start <= start && res->end >= end) {
//			if (!(res->flags & IORESOURCE_BUSY)) {
//				p = &res->child;
//				continue;
//			}
//			if (res->start != start || res->end != end)
//				break;
//			*p = res->sibling;
//			write_unlock(&resource_lock);
//			if (res->flags & IORESOURCE_MUXED)
//				wake_up(&muxed_resource_wait);
//			free_resource(res);
//			return;
//		}
//		p = &res->sibling;
//	}

//	write_unlock(&resource_lock);

//	printk(KERN_WARNING "Trying to free nonexistent resource "
//		"<%016llx-%016llx>\n", (unsigned long long)start,
//		(unsigned long long)end);
//}
//EXPORT_SYMBOL(__release_region);

//#ifdef CONFIG_MEMORY_HOTREMOVE
///**
// * release_mem_region_adjustable - release a previously reserved memory region
// * @start: resource start address
// * @size: resource region size
// *
// * This interface is intended for memory hot-delete.  The requested region
// * is released from a currently busy memory resource.  The requested region
// * must either match exactly or fit into a single busy resource entry.  In
// * the latter case, the remaining resource is adjusted accordingly.
// * Existing children of the busy memory resource must be immutable in the
// * request.
// *
// * Note:
// * - Additional release conditions, such as overlapping region, can be
// *   supported after they are confirmed as valid cases.
// * - When a busy memory resource gets split into two entries, the code
// *   assumes that all children remain in the lower address entry for
// *   simplicity.  Enhance this logic when necessary.
// */
//void release_mem_region_adjustable(resource_size_t start, resource_size_t size)
//{
//	struct resource *parent = &iomem_resource;
//	struct resource *new_res = NULL;
//	bool alloc_nofail = false;
//	struct resource **p;
//	struct resource *res;
//	resource_size_t end;

//	end = start + size - 1;
//	if (WARN_ON_ONCE((start < parent->start) || (end > parent->end)))
//		return;

//	/*
//	 * We free up quite a lot of memory on memory hotunplug (esp., memap),
//	 * just before releasing the region. This is highly unlikely to
//	 * fail - let's play save and make it never fail as the caller cannot
//	 * perform any error handling (e.g., trying to re-add memory will fail
//	 * similarly).
//	 */
//retry:
//	new_res = alloc_resource(GFP_KERNEL | (alloc_nofail ? __GFP_NOFAIL : 0));

//	p = &parent->child;
//	write_lock(&resource_lock);

//	while ((res = *p)) {
//		if (res->start >= end)
//			break;

//		/* look for the next resource if it does not fit into */
//		if (res->start > start || res->end < end) {
//			p = &res->sibling;
//			continue;
//		}

//		/*
//		 * All memory regions added from memory-hotplug path have the
//		 * flag IORESOURCE_SYSTEM_RAM. If the resource does not have
//		 * this flag, we know that we are dealing with a resource coming
//		 * from HMM/devm. HMM/devm use another mechanism to add/release
//		 * a resource. This goes via devm_request_mem_region and
//		 * devm_release_mem_region.
//		 * HMM/devm take care to release their resources when they want,
//		 * so if we are dealing with them, let us just back off here.
//		 */
//		if (!(res->flags & IORESOURCE_SYSRAM)) {
//			break;
//		}

//		if (!(res->flags & IORESOURCE_MEM))
//			break;

//		if (!(res->flags & IORESOURCE_BUSY)) {
//			p = &res->child;
//			continue;
//		}

//		/* found the target resource; let's adjust accordingly */
//		if (res->start == start && res->end == end) {
//			/* free the whole entry */
//			*p = res->sibling;
//			free_resource(res);
//		} else if (res->start == start && res->end != end) {
//			/* adjust the start */
//			WARN_ON_ONCE(__adjust_resource(res, end + 1,
//						       res->end - end));
//		} else if (res->start != start && res->end == end) {
//			/* adjust the end */
//			WARN_ON_ONCE(__adjust_resource(res, res->start,
//						       start - res->start));
//		} else {
//			/* split into two entries - we need a new resource */
//			if (!new_res) {
//				new_res = alloc_resource(GFP_ATOMIC);
//				if (!new_res) {
//					alloc_nofail = true;
//					write_unlock(&resource_lock);
//					goto retry;
//				}
//			}
//			new_res->name = res->name;
//			new_res->start = end + 1;
//			new_res->end = res->end;
//			new_res->flags = res->flags;
//			new_res->desc = res->desc;
//			new_res->parent = res->parent;
//			new_res->sibling = res->sibling;
//			new_res->child = NULL;

//			if (WARN_ON_ONCE(__adjust_resource(res, res->start,
//							   start - res->start)))
//				break;
//			res->sibling = new_res;
//			new_res = NULL;
//		}

//		break;
//	}

//	write_unlock(&resource_lock);
//	free_resource(new_res);
//}
//#endif	/* CONFIG_MEMORY_HOTREMOVE */

//#ifdef CONFIG_MEMORY_HOTPLUG
//static bool system_ram_resources_mergeable(struct resource *r1,
//					   struct resource *r2)
//{
//	/* We assume either r1 or r2 is IORESOURCE_SYSRAM_MERGEABLE. */
//	return r1->flags == r2->flags && r1->end + 1 == r2->start &&
//	       r1->name == r2->name && r1->desc == r2->desc &&
//	       !r1->child && !r2->child;
//}

///*
// * merge_system_ram_resource - mark the System RAM resource mergeable and try to
// * merge it with adjacent, mergeable resources
// * @res: resource descriptor
// *
// * This interface is intended for memory hotplug, whereby lots of contiguous
// * system ram resources are added (e.g., via add_memory*()) by a driver, and
// * the actual resource boundaries are not of interest (e.g., it might be
// * relevant for DIMMs). Only resources that are marked mergeable, that have the
// * same parent, and that don't have any children are considered. All mergeable
// * resources must be immutable during the request.
// *
// * Note:
// * - The caller has to make sure that no pointers to resources that are
// *   marked mergeable are used anymore after this call - the resource might
// *   be freed and the pointer might be stale!
// * - release_mem_region_adjustable() will split on demand on memory hotunplug
// */
//void merge_system_ram_resource(struct resource *res)
//{
//	const unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
//	struct resource *cur;

//	if (WARN_ON_ONCE((res->flags & flags) != flags))
//		return;

//	write_lock(&resource_lock);
//	res->flags |= IORESOURCE_SYSRAM_MERGEABLE;

//	/* Try to merge with next item in the list. */
//	cur = res->sibling;
//	if (cur && system_ram_resources_mergeable(res, cur)) {
//		res->end = cur->end;
//		res->sibling = cur->sibling;
//		free_resource(cur);
//	}

//	/* Try to merge with previous item in the list. */
//	cur = res->parent->child;
//	while (cur && cur->sibling != res)
//		cur = cur->sibling;
//	if (cur && system_ram_resources_mergeable(cur, res)) {
//		cur->end = res->end;
//		cur->sibling = res->sibling;
//		free_resource(res);
//	}
//	write_unlock(&resource_lock);
//}
//#endif	/* CONFIG_MEMORY_HOTPLUG */

///*
// * Managed region resource
// */
//static void devm_resource_release(struct device *dev, void *ptr)
//{
//	struct resource **r = ptr;

//	release_resource(*r);
//}

///**
// * devm_request_resource() - request and reserve an I/O or memory resource
// * @dev: device for which to request the resource
// * @root: root of the resource tree from which to request the resource
// * @new: descriptor of the resource to request
// *
// * This is a device-managed version of request_resource(). There is usually
// * no need to release resources requested by this function explicitly since
// * that will be taken care of when the device is unbound from its driver.
// * If for some reason the resource needs to be released explicitly, because
// * of ordering issues for example, drivers must call devm_release_resource()
// * rather than the regular release_resource().
// *
// * When a conflict is detected between any existing resources and the newly
// * requested resource, an error message will be printed.
// *
// * Returns 0 on success or a negative error code on failure.
// */
//int devm_request_resource(struct device *dev, struct resource *root,
//			  struct resource *new)
//{
//	struct resource *conflict, **ptr;

//	ptr = devres_alloc(devm_resource_release, sizeof(*ptr), GFP_KERNEL);
//	if (!ptr)
//		return -ENOMEM;

//	*ptr = new;

//	conflict = request_resource_conflict(root, new);
//	if (conflict) {
//		dev_err(dev, "resource collision: %pR conflicts with %s %pR\n",
//			new, conflict->name, conflict);
//		devres_free(ptr);
//		return -EBUSY;
//	}

//	devres_add(dev, ptr);
//	return 0;
//}
//EXPORT_SYMBOL(devm_request_resource);

//static int devm_resource_match(struct device *dev, void *res, void *data)
//{
//	struct resource **ptr = res;

//	return *ptr == data;
//}

///**
// * devm_release_resource() - release a previously requested resource
// * @dev: device for which to release the resource
// * @new: descriptor of the resource to release
// *
// * Releases a resource previously requested using devm_request_resource().
// */
//void devm_release_resource(struct device *dev, struct resource *new)
//{
//	WARN_ON(devres_release(dev, devm_resource_release, devm_resource_match,
//			       new));
//}
//EXPORT_SYMBOL(devm_release_resource);

//struct region_devres {
//	struct resource *parent;
//	resource_size_t start;
//	resource_size_t n;
//};

//static void devm_region_release(struct device *dev, void *res)
//{
//	struct region_devres *this = res;

//	__release_region(this->parent, this->start, this->n);
//}

//static int devm_region_match(struct device *dev, void *res, void *match_data)
//{
//	struct region_devres *this = res, *match = match_data;

//	return this->parent == match->parent &&
//		this->start == match->start && this->n == match->n;
//}

//struct resource *
//__devm_request_region(struct device *dev, struct resource *parent,
//		      resource_size_t start, resource_size_t n, const char *name)
//{
//	struct region_devres *dr = NULL;
//	struct resource *res;

//	dr = devres_alloc(devm_region_release, sizeof(struct region_devres),
//			  GFP_KERNEL);
//	if (!dr)
//		return NULL;

//	dr->parent = parent;
//	dr->start = start;
//	dr->n = n;

//	res = __request_region(parent, start, n, name, 0);
//	if (res)
//		devres_add(dev, dr);
//	else
//		devres_free(dr);

//	return res;
//}
//EXPORT_SYMBOL(__devm_request_region);

//void __devm_release_region(struct device *dev, struct resource *parent,
//			   resource_size_t start, resource_size_t n)
//{
//	struct region_devres match_data = { parent, start, n };

//	__release_region(parent, start, n);
//	WARN_ON(devres_destroy(dev, devm_region_release, devm_region_match,
//			       &match_data));
//}
//EXPORT_SYMBOL(__devm_release_region);

///*
// * Reserve I/O ports or memory based on "reserve=" kernel parameter.
// */
//#define MAXRESERVE 4
//static int __init reserve_setup(char *str)
//{
//	static int reserved;
//	static struct resource reserve[MAXRESERVE];

//	for (;;) {
//		unsigned int io_start, io_num;
//		int x = reserved;
//		struct resource *parent;

//		if (get_option(&str, &io_start) != 2)
//			break;
//		if (get_option(&str, &io_num) == 0)
//			break;
//		if (x < MAXRESERVE) {
//			struct resource *res = reserve + x;

//			/*
//			 * If the region starts below 0x10000, we assume it's
//			 * I/O port space; otherwise assume it's memory.
//			 */
//			if (io_start < 0x10000) {
//				res->flags = IORESOURCE_IO;
//				parent = &ioport_resource;
//			} else {
//				res->flags = IORESOURCE_MEM;
//				parent = &iomem_resource;
//			}
//			res->name = "reserved";
//			res->start = io_start;
//			res->end = io_start + io_num - 1;
//			res->flags |= IORESOURCE_BUSY;
//			res->desc = IORES_DESC_NONE;
//			res->child = NULL;
//			if (request_resource(parent, res) == 0)
//				reserved = x+1;
//		}
//	}
//	return 1;
//}
//__setup("reserve=", reserve_setup);

///*
// * Check if the requested addr and size spans more than any slot in the
// * iomem resource tree.
// */
//int iomem_map_sanity_check(resource_size_t addr, unsigned long size)
//{
//	struct resource *p = &iomem_resource;
//	int err = 0;
//	loff_t l;

//	read_lock(&resource_lock);
//	for (p = p->child; p ; p = r_next(NULL, p, &l)) {
//		/*
//		 * We can probably skip the resources without
//		 * IORESOURCE_IO attribute?
//		 */
//		if (p->start >= addr + size)
//			continue;
//		if (p->end < addr)
//			continue;
//		if (PFN_DOWN(p->start) <= PFN_DOWN(addr) &&
//		    PFN_DOWN(p->end) >= PFN_DOWN(addr + size - 1))
//			continue;
//		/*
//		 * if a resource is "BUSY", it's not a hardware resource
//		 * but a driver mapping of such a resource; we don't want
//		 * to warn for those; some drivers legitimately map only
//		 * partial hardware resources. (example: vesafb)
//		 */
//		if (p->flags & IORESOURCE_BUSY)
//			continue;

//		printk(KERN_WARNING "resource sanity check: requesting [mem %#010llx-%#010llx], which spans more than %s %pR\n",
//		       (unsigned long long)addr,
//		       (unsigned long long)(addr + size - 1),
//		       p->name, p);
//		err = -1;
//		break;
//	}
//	read_unlock(&resource_lock);

//	return err;
//}

//#ifdef CONFIG_STRICT_DEVMEM
//static int strict_iomem_checks = 1;
//#else
//static int strict_iomem_checks;
//#endif

///*
// * check if an address is reserved in the iomem resource tree
// * returns true if reserved, false if not reserved.
// */
//bool iomem_is_exclusive(u64 addr)
//{
//	struct resource *p = &iomem_resource;
//	bool err = false;
//	loff_t l;
//	int size = PAGE_SIZE;

//	if (!strict_iomem_checks)
//		return false;

//	addr = addr & PAGE_MASK;

//	read_lock(&resource_lock);
//	for (p = p->child; p ; p = r_next(NULL, p, &l)) {
//		/*
//		 * We can probably skip the resources without
//		 * IORESOURCE_IO attribute?
//		 */
//		if (p->start >= addr + size)
//			break;
//		if (p->end < addr)
//			continue;
//		/*
//		 * A resource is exclusive if IORESOURCE_EXCLUSIVE is set
//		 * or CONFIG_IO_STRICT_DEVMEM is enabled and the
//		 * resource is busy.
//		 */
//		if ((p->flags & IORESOURCE_BUSY) == 0)
//			continue;
//		if (IS_ENABLED(CONFIG_IO_STRICT_DEVMEM)
//				|| p->flags & IORESOURCE_EXCLUSIVE) {
//			err = true;
//			break;
//		}
//	}
//	read_unlock(&resource_lock);

//	return err;
//}

//struct resource_entry *resource_list_create_entry(struct resource *res,
//						  size_t extra_size)
//{
//	struct resource_entry *entry;

//	entry = kzalloc(sizeof(*entry) + extra_size, GFP_KERNEL);
//	if (entry) {
//		INIT_LIST_HEAD(&entry->node);
//		entry->res = res ? res : &entry->__res;
//	}

//	return entry;
//}
//EXPORT_SYMBOL(resource_list_create_entry);

//void resource_list_free(struct list_head *head)
//{
//	struct resource_entry *entry, *tmp;

//	list_for_each_entry_safe(entry, tmp, head, node)
//		resource_list_destroy_entry(entry);
//}
//EXPORT_SYMBOL(resource_list_free);

//#ifdef CONFIG_DEVICE_PRIVATE
//static struct resource *__request_free_mem_region(struct device *dev,
//		struct resource *base, unsigned long size, const char *name)
//{
//	resource_size_t end, addr;
//	struct resource *res;

//	size = ALIGN(size, 1UL << PA_SECTION_SHIFT);
//	end = min_t(unsigned long, base->end, (1UL << MAX_PHYSMEM_BITS) - 1);
//	addr = end - size + 1UL;

//	for (; addr > size && addr >= base->start; addr -= size) {
//		if (region_intersects(addr, size, 0, IORES_DESC_NONE) !=
//				REGION_DISJOINT)
//			continue;

//		if (dev)
//			res = devm_request_mem_region(dev, addr, size, name);
//		else
//			res = request_mem_region(addr, size, name);
//		if (!res)
//			return ERR_PTR(-ENOMEM);
//		res->desc = IORES_DESC_DEVICE_PRIVATE_MEMORY;
//		return res;
//	}

//	return ERR_PTR(-ERANGE);
//}

///**
// * devm_request_free_mem_region - find free region for device private memory
// *
// * @dev: device struct to bind the resource to
// * @size: size in bytes of the device memory to add
// * @base: resource tree to look in
// *
// * This function tries to find an empty range of physical address big enough to
// * contain the new resource, so that it can later be hotplugged as ZONE_DEVICE
// * memory, which in turn allocates struct pages.
// */
//struct resource *devm_request_free_mem_region(struct device *dev,
//		struct resource *base, unsigned long size)
//{
//	return __request_free_mem_region(dev, base, size, dev_name(dev));
//}
//EXPORT_SYMBOL_GPL(devm_request_free_mem_region);

//struct resource *request_free_mem_region(struct resource *base,
//		unsigned long size, const char *name)
//{
//	return __request_free_mem_region(NULL, base, size, name);
//}
//EXPORT_SYMBOL_GPL(request_free_mem_region);

//#endif /* CONFIG_DEVICE_PRIVATE */

//static int __init strict_iomem(char *str)
//{
//	if (strstr(str, "relaxed"))
//		strict_iomem_checks = 0;
//	if (strstr(str, "strict"))
//		strict_iomem_checks = 1;
//	return 1;
//}

//__setup("iomem=", strict_iomem);
